A clear and strong proof for demonstrating the corpuscular nature of the light and other particles is the left-right or right-inversion proof.
The different nature between particles and waves make that any of them has also different manner of emission.
Then, if we revise and deduce their types of emission, we can demonstrate their nature.

-- Particles have to be propagated in straight line, separately one from the other ones.
So, any particle traces a straight line without expansion.

-- Contrarily, waves have the expansion characteristic that gives to each one of them the property of being expanding from the point of emission toward the exterior in radial way.
So, waves trace an expanding oscillation in circular form.

Slit and camera obscure experiments.

As we know, the slit or camera obscure experiment consists of an emission focus, a plate with a slit or hole for the transit of particles and a screen of impact to see the resulting marks.

Particles

So, given a focus of emission of particles, if we situate in the field of emission a screen with a slit or hole that allow the pass of a single ray of particles, we can see as the particles when having to follow a straight line, they produce in the screen of impact the drawing of the focus but in the inverse sense.
So the emitted particles that pass through the slit or hole of the plate, when going in straight line, form in the screen of impact the figure of the focus (or landscape) that emits the particles, but always in inverse form.

Waves

Contrary, the waves have the expansion characteristic and when the emitted waves reach the slit or hole in the plate, they begin newly the expansion from this slit or hole in radial way, but maintaining the same sense of expansion that they brought.

So, when the screen of impact shows us the figure of the focus in the inverse sense, this says us that particles and light are definitively corpuscles and not waves.

Important question:
If light were waves, these must to unite forming composed waves what impedes the images definition and vision of things.
The vision and definition quality needs of the emission of light in individual points of particles (photon) that defines us all and each one of the points that compose an image or landscape.

So if photons were waves, in the reception of images we alone can see a mixture of lights and shadows without any image definition.

But not alone these proofs speak us about the corpuscular nature of light and particles. In my experiments of this theme you can see better the different cases and circumstances.